The U.S. military was searching on Sunday for three American soldiers who went missing in an al Qaeda stronghold near Baghdad after a raid killed five members of a joint U.S.-Iraqi patrol.

North of the capital, a truck bomb near the office of a leading Kurdish political party killed at least 30 people and wounded 50 in the town of Makhmour. It came four days after a truck bomb killed at least 15 people in the nearby city of Arbil, capital of the autonomous Iraqi region of Kurdistan.

The patrol of seven U.S. soldiers and one Iraqi army interpreter were ambushed in a rural area south of Baghdad known as the Sunni "Triangle of Death" -- the same area where two U.S. soldiers were abducted by al Qaeda insurgents last year before their mutilated bodies were found.

"We can establish now the identity of three of the American soldiers who were killed and the one Iraqi Army interpreter that was killed. So the identification of four of the five is now complete and the fifth one is still ongoing," Major-General William Caldwell, chief military spokesman, said.

"We will make every effort available to find our three missing soldiers," Caldwell told a news conference.

U.S.-led troops backed by helicopters and jets combed orchards, searched farms and threw up roadblocks in a massive hunt for the missing soldiers west of the town of Mahmudiya.

Residents said the patrol was ambushed by insurgents after it struck a roadside bomb on a rural road in an area of palm groves called Shibaiya, near the town of Yusufiya.

"We saw smoke rise from the area. Three vehicles were on fire and a fourth one had fallen into a canal," said a farmer.

"U.S. forces cordoned off the area and made arrests," the farmer told Reuters as U.S. helicopters hovered overhead.

The mayor of Mahmudiya, Muayed al-Ameri, also said the patrol had been ambushed.

Last June, al Qaeda gunmen snatched two U.S. soldiers at a checkpoint in Yusufiya. Their mutilated and booby-trapped bodies were found days later after a search by thousands of troops.

Some 30,000 additional U.S. troops are being deployed in Baghdad in what is seen as a final push to halt a slide into all-out civil war between majority Shi'ites and Sunni Arabs.

The three-month-old plan is also aimed at securing areas outside Baghdad from where Sunni Arab militants are staging attacks against Shi'ites in the capital and elsewhere.

Colonel Abdul Qadir al Harky said the bomb in Makhmour in the north of Iraq went off in an area with several government offices and there were many bodies under the rubble.

Other security sources said the KDP was having a local meeting at the time of the attack. The KDP is the party of Massoud Barzani, leader of the autonomous Kurdish region.

The attack near the Kurdish interior ministry in Arbil last week, which was claimed by al Qaeda, raised fears among ethnic Kurds that their relatively peaceful region would become a target of more violence to come.

(Additional reporting by Shamal Aqrawi in Arbil)

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